1. Field of the Invention
The invention generally relates to an image processing method and an optical system, and more particularly, to a method of stitching fundus images of an eye of an animal and a camera system.
2. Description of Related Art
Eyes are the window to the soul, and people see the world through their eyes. The cone and rod cells responsible for color and light reception in the eye are located in the retina at the fundus and are the photoreceptors for converting light into physiological electrical signals in the human body. The blood vessels for supplying blood and nutrients to the eye are also located at the fundus. When a vascular hyperplasia or rupture occurs on the fundus (for example, macular degeneration), the cone and rod cells in the retina may die and accordingly the patient may lose his or her eyesight. Thus, it is very important to observe and track fundus images in the diagnosis and prevention of eye diseases.
Generally, due to the limitation in the size of human pupil, the conventional fundus image capturing technique can capture a fundus image within a range of about 30° to 40° from each shooting angle. Thus, to capture images of the brim of the fundus, the patient has to stare at a reference point and then move his or her eyes around the reference point at a slow and steady speed. Through this technique, a plurality of fundus images can be captured. After that, the fundus images are merged by using a data processing apparatus (for example, a computer) and a special image synthesis software. However, because these fundus images are not captured all together, they have different exposure values and white balance values. In addition, the fundus images need to be corrected before they are stitched, which causes the correction of the fundus images to be complicated and the quality of the stitched image to be reduced. With the reduced quality of the stitched image, capillary vessels may be difficult to identify and accordingly diagnosis may not be made or the best treatment timing may even be missed out. Thereby, how to obtain complete and clear fundus images in a short time is a major subject in the medical industry.